An interface module for transmitting a digital video signal includes: a transmitting interface unit which is designed to be connected to a host device for outputting a video signal, and which has a cable connection consisting of a 4-core optical fiber cable and a 4-core male connector provided at one end thereof; a receiving interface unit having a cable connection designed to be connected to a video output display unit and consisting of a 4-core optical fiber cable and a 4-core male connector provided at one end thereof; and an optical cable unit for transmitting TMDS signals consisting of RGB signals and clock signals. The transmitting and receiving interface units are interconnected by the optical cable unit. The transmitting interface unit includes a second integrated circuit outputting identification information (DDC signal) associated with the video output display unit.